Problem: Simplify to lowest terms. $\dfrac{56}{63}$
Explanation: What is the greatest common factor (GCD) of 56 and 63? $56 = 2\cdot2\cdot2\cdot7$ $63 = 3\cdot3\cdot7$ $\mbox{GCD}(56, 63) = 7$ $\dfrac{56}{63} = \dfrac{8 \cdot 7}{ 9\cdot 7}$ $\hphantom{\dfrac{56}{63}} = \dfrac{8}{9} \cdot \dfrac{7}{7}$ $\hphantom{\dfrac{56}{63}} = \dfrac{8}{9} \cdot 1$ $\hphantom{\dfrac{56}{63}} = \dfrac{8}{9}$